Originally Posted by bchurch
It just means that there isn't a perfect seal on your primary, no worries your fermentation is putting out enough co2 to blanket your beer. I wouldn't rack yet.
I agree with this fellow...
You have a small leak and there is no reason for worries.
The chances that something would get in is so slight as not to be measueable... assuming you house is not a microb-factory.
I know people who do "open fermentation", I am not brave enough but I don't worry about a small leak.
I have even tossed a clean, Star-San towel over a bucket lid with out a airlock and had no problems...